Method and apparatus for dehydration



April 29, 1958 H, A TOULMlN, JR Re. 24,466

METHOD AND APPARATUS FOR DEHYDRATION Original Filed- Jan. 18, 1950 2Sheets-Sheet 1 N O a :8

C .L 1l ,f i d i* U-I v g /m/mroR HARRY A. rouLM//v JA.

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HTTORNEYS April 29, 1958 H, A, TOULMIN, JR Re. 24,466

METHOD AND APPARATUS FOR DEHYDRATION original Filed Jan. 18, 195o 2Sheets-Sheet 2 znucoNcEuTRATloN E @w w mw M u W m ym Aff. n. `P. y w,

United States Patent 2O IVIETHOD AND APPARATUS FOR DEHYDRATION Harry A.Toulmin, Jr., Dayton, Ohio, assignor, by mesne assignments, to UnionCarbide Corporation, New York, N. Y., a corporation of New York OriginalNo. 2,657,551, dated November 3, 1953, Serial No. 139,174, January 18,1950. Application for reissue August 3, 1954, Serial No. 447,695

y 13 Claims. (Cl. 99-205) Matter enclosed in heavy brackets appears inthe original patent but forms uo part of this reissue specification;matter printed in italics indicates the additions made by reissue.

This invention relates to a method and apparatus for concentratingaqueous substances by the dehydration thereof through a freezingprocess.

The concentration of fruit` and vegetable juices has heretoforegenerally been accomplished by the application of heat or vaccum orboth, in order to bring about evaporation of the water to concentratethe substance to the desired degree. This has the disadvantage of beingrather time consuming and, in addition, causes a substantial change inthe llavor of the substance, so that when it is reconstituted by theaddition of the same amount of water that was removed therefrom, it ismuch less palatable, and, accordingly, has not met with wide publicapproval.

The concentration of juices as set forth above is also accompanied by aconsiderable loss of the vitamin content of the juice, so that itusually has considerably less food value when reconstituted than it hadbefore.

Certain other substances which it may be desired to concentrate containingredientswhich may be injured by the application of heat, either as toactual chemical and physical structure, or as to color or otherqualities, and, accordingly, substances of this nature have notheretofore successfully been concentrated by dehydration.

The principal object of the present invention is to provide a method andapparatus for concentrating aqueous substances by dehydration through afreezing process whereby the disadvantages referred to above inconnection with prior art processes are substantially completelyeliminated.

Another object of this invention is to provide an arrangement wherebyvery viscous substances can be successfully treated in order to removethe water therefrom.

A still further object is the provision of a method and apparatus fordehydrating substances by freezing, wherein the substance being treatedis passed through a plurality of stages `so that lthe number of stagescan be increased or decreased to obtain the desired degree ofconcentration.

These and other objects and advantages will become more apparent uponreference to the following description taken in connection with theaccompanying drawings, in which:

Figure 1 is a sectional view through one form which ani apparatusaccordingv to my invention may take;

Figure 2 is a view showing the apparatus of this invention arranged forconcentrating substances according to a three-stage process;

Figure 3 is a -ow chart showing the movement through the process of thesubstance being concentrated and the ice removed therefrom;

Figure 4 is a diagrammatic view of another form which the apparatusaccording to my invention rnay take; and

Figure 5 is a chart outlining the `sequence of operations in connectionwith the apparatus in Figure 4.

Fice

Referring to the drawings, in particular to Figure 1, thearrangementshown therein comprises a tank or container 10 supported in atiltable carrier 12 mounted on trunnions 14, adapted for being tilted byhand wheel 16. A space 18 is provided between container 10 andsupporting means 12, and within this space are coils 20 which areoperable for chilling container 10 when receiving a refrigerating mediumas controlled by the valve 60.

' Vertically disposed over the axis of container 10 is a hydraulic motor22, including reciprocal ram 24, con-y nected to a yoke 26, whichterminates at its lower end in a part 28, adapted for engaging andclosing the upper end of container 10. Mounted on yoke 26 is a motor 30having a shaft 32 extending through part 28, and having thereon anagitator 34 adapted for being positioned within container 10 in order toagitate the contents thereof.

When supporting means 12 is tilted by hand wheel 16, contents ofcontainer 10 are delivered to a centrifuge 36 which has a perforatedbasket 38 therein, which, when rotated at high speed, throws the liquidtherefrom while retaining ice therein. The liquid thrown outward frombasket 38 passes downwardly through discharge basket 40 into a. tank orsump 42 to which is connected a pump 44.

In Figure 2 it will be seen that a three-stage process is set up, andthat eachof the stages comprises mechanisms substantially identical withthat just described in connection with Figure 1.

In Figure 2 the various elements of the apparatus in stage 1 areidentified by the same reference numerals as employed in Figure 1, Whilein stage 2 the same numerals are employed with the addition of asubscript a, and in stage 3 the same numerals are employed with theaddition of a subscript b.

Pump 44 which draws liquid from stage l delivers through a pipe 46 whichhas one branch pipe 48 leading through valve 50 so as to deliver liquidto container 10a, and another branch pipe 52 leading through valve 54,so that a certain portion of the liquid which pump 44 draws from sump 42can be retluxed back through stage 1.

Sump 42a associated with stage 2 is similarly connected through its pump44a so that a portion of the liquid extracted in centrifuge 38a can bereuxed through stage 2 and a portion thereof delivered to stage 3,

The sump of stage 3, not shown, is also connected so that a portion orall thereof can be delivered through pipe 48b and valve 50h to productstage, while another portion can be delivered through pipes 52b andvalve 54b back to stage l.

In operation, the containers 10, 10a, and 10b are adapted for being ashheated by passing a heating medium such as steam through the coil 20, ascontrolled by the valve 61, or about the outside of the containers, sothat after an ice film has formed inside the said containers it can beashed loose therefrom, and then, when the containers are tilted to thedischarge position, all of the ice and liquid therein will be deliveredto the associated centrifuge.

In most instances, I have found that it is satisfactory to operate stage1 at about minus 3 degrees centigrade,

stage 2 from about minus 8 to minus 15 degrees centigrade, and stage 3at about minus 25 degrees centigrade.v

It will be understood that the particular temperatures employed will`vary with the juices being concentrated and with the number of stagesthrough which it is desired to carry it, and with the ultimate degree ofconcentration desired, and that the temperatures referred to above aremerely examples of one operative process which has been carried out.

It has `been mentioned before that the process of this` I Linvention isadapted for treating highly viscous substances,

and for this purpose the agitator 34 is employed. By utilizing theagitator 34, the substance in the container is kept in motion, and allparts of it are brought into contact with the periphery of the saidcontainer so that a freezing action can take place. This materiallyspeeds up the processl and insures a high efficiency of ice re-v moval.

It is preferable, in carrying out the process, to convey the ice fromeach centrifuge to the refrigerated container of the preceding stage. Inthis manner ice crystals formed in one stage are supplied to thepreceding stage and act as nuclei about which larger ice crystals cangrow in the substance in the container. This not only further increasesthe efficiency of the process, but also, by causing the ice to passthrough the process in counterflow relation to the flow of the liquid,the ice is always removed from the liquid at the point of leastconcentration, while the liquid is removed from the process at its pointof greatest concentration.

Figure 4 shows a somewhat different arrangement, which operates,however, on substantially the same principles as that described inconnection with Figures 1 and 2.

In Figure 4 the lirst stage of the process is carried out within atiltable container comprising the inner container 60 and the outercontainer62 between which there isa space 64 for supplying refrigerantto chill the inner container.

The flash heater 66' surrounds the inner container and is employed forbreaking the ice off the container. Agitator means represented bymultiple blades 68 on shaft 70 driven through gear 72 from a power means74 provide agitating means for keeping the liquid stirred up within theinner container. A lift cable 76 is provided vfor elevating theagitating means upwardly out of the inner container so that it can betilted to the position shown in dot-dash lines at B, where the liquid inthe inner container will pour into inner container 60a of the secondstage.

According to this process, the container then is tilted to the positionindicated by the letter C, and any remaining liquid therein will ow intothe centrifuge 80. At the same time, the ice is loosened within thecontainer by the flash heater and is also discharged into the saidcentrifuge.

y The centrifuge is operative to extract the liquid from the ice and todischarge it into pipe 82 and valve 84 into a collecting means,indicated at 86. The centrifuge is also tiltable so the ice can bedischarged into an ice trough 88, when a certain portion is reuxed backthrough the process.

In stage 2 the same apparatus is employed as is employed in stage 1,except that when it is desired to empty the container in stage 2, it isfirst tilted rightwardly to the position indicated by the dot-dash linesat D," so the juice will run therefrom to a juice trough 90. Thereafter,the container of stage 2 is tilted leftwardly to the position indicatedby the dot-dash lines at E, and the ice discharged therefrom after ithas been broken up by the action of the llash heater.

The parts of the apparatus employed in stage 2 which correspond to thoseemployed in stage l are identified by the same reference numerals withthe addition of a subscript A.

It has been found in practice that the first concentration canadvantageously be carried out at from 3 to 10 degrees below zerocentigrade, while the second stage can be carried out at from to 25degrees below zero centigrade, but it will be understood that thesetemperatures are merely exemplary, and that other temperatures could beemployed where the nature of the substance being processed indicated.

Also, while I have shown a two-stage process in Figure 4, it will beunderstood that as lmany'stages as necessary to eiect the desired degreeof concentration could be em- 'filployed under the same principles ofoperation, and the same advantages would obtain.

By practicing my invention and apparatus of the type illustrated, it isfound that juices such as fruit and vegetable juices can be concentratedvery rapidly, thereby avoiding deleterious exposure to the atmosphere,the resulting concentrate can be reconstituted to its original dilutionby the addition of pure water and have substantially the same avor offresh juice, and the value of the reconstituted juice as a food is notimpaired because it has substantially the same vitamin content as beforeit was processed.

It will be understood that I do not wish to be limited to the exactproportions, ratios, and other factors specilically set forth in theforegoing description and the accompanying drawings, but desire tocomprehend such changes thereof as may be further desirable to adapt myinvention to different conditions and usages.

I claim:

1. In an apparatus for freeze-dehydrating aqueous substances; a tiltablysupported container, means for chilling the container to cause ice toform on the walls thereof when the substance to be dehydrated is in thecontainer, a centrifuge positioned to receive at least a portion of thecontents of the container, means for tilting said container, and meansfor flash heating the container to loosen the ice on the walls thereof.

2. In an apparatus for freeze-dehydrating aqueous substances; a tiltablysupported container, means for chilling l the container to cause ice toform on the walls thereof when the substance to be dehydrated is in thecontainer, a centrifuge positioned to receive at least a portion of thecontents of the container, means for tilting said container, means forflash heating the container to loosen the ice on the walls thereof sotilting of the container will discharge its entire contents to thecentrifuge, and a movably mounted agitator positioned over the containerso as to be movable therein when the container is upright.

3. In an apparatus for freeze-dehydrating aqueous substances; aplurality o-f tiltably supported containers, a centrifuge for eachcontainer positioned to receive the contents therefrom when therespective container is tilted on its support, means for chilling saidcontainers to cause ice to form on the walls thereof when the substanceto be treated is in the containers, means for flash heating thecontainers to release the ice therefrom for discharge to the centrifugeswith the liquid in the containers, said centrifuges being operable toseparate the ice from the liquid, and a pump for each centrifugeconnected to pump the liquid therefrom to another container, whereby theliquid becomes more concentrated by the removal of water therefrom asice, said containers being chilled to progressively lower temperaturesin the direction of movement of the substance therethrough.

4. In an apparatus for freeze-dehydrating; a tiltable container, meansfor refrigerating the container, a second container positioned beneathand to one side of said tiltable container so as to receive liquidstherefrom and including means for tilting said container, a centrifugepositioned beneath the tiltable container, and a flash heater for saidtiltable container whereby the said tiltable container can be invertedand the flash heater energized to release ice from the walls of thecontainer to the centrifuge.

5. In an apparatus for freeze-dehydrating; a tiltable container, meansfor refrigerating the container, an agitator movable into the containerfrom above for agitating substances in the container and retractable topermit tilting of the container, a second container positioned beneathand to one side of said tiltable container so as to receive liquidstherefrom and including a centrifuge positioned beneath the tiltablecontainer, and a flash heater for said tiltable container whereby thesaid tiltable container can be inverted and Vthe ilash heater energizedto release ice from the walls of the container to the centrifuge.

6. In an apparatus for freeze-dehydrating; a pair of tiltablerefrigerated containers for the material being dehydrated, an icereceiver, and a liquid receiver; said containers and receivers being soarranged that tilting of one of the containers will position it todischarge to the other container, and inverting of the one containerwill position it to discharge to the ice receiver, and tilting of theother container in respective opposite directions will position it todischarge to said liquid receiver and ice receiver, respectively, andmeans for ilash heating the containers to release ice from the wallsthereof when positioned to discharge to said ice receiver.

7. In an apparatus for freeze-dehydrating; a pair of tiltablerefrigerated containers for the material being dehydrated, an icereceiver, and a liquid receiver; said containers and receivers being soarranged that tilting of one of the containers will position it todischarge to the other container, and inverting of the one containerwill position it to discharge to the ice receiver, and tilting of theother container in respective opposite directions will position it todischarge to said liquid receiver and ice receiver, respectively, andmeans for flash heating the containers to release ice from the wallsthereof when positioned to discharge to said ice receiver, each of saidcontainers having a retractible agitator suspended from thereover.

8. In an apparatus for freeze-dehydrating; a pair of tiltablerefrigerated containers for the material being dehydrated, an icereceiver, and a liquid receiver; said containers and receivers being soarranged that tilting of one of the containers will position it todischarge to the other container, and inverting of the one containerwill position it to discharge to the ice receiver, and tilting of theother container in respective opposite directions will position it todischarge to said liquid receiver and ice receiver, respectively, andmeans for flash heating the containers to release ice from the wallsthereof when positioned to discharge to said ice receiver, said othercontainer being refrigerated to a lower temperature than said onecontainer.

9. In an apparatus for freeze-dehydrating; a pair of tiltablerefrigerated containers for the material being dehydrated, an icereceiver, and a liquid receiver; said containers and receivers being soarranged that tilting of one of the containers will position it todischarge to the other container, and inverting of the one containerwill position it to discharge to the ice receiver, and tilting of theother container in respective opposite directions will position it todischarge to said liquid receiver and ice receiver, respectively, andmeans for ash heating the containers to release ice from the Wallsthereof when positioned to discharge to said ice receiver, said icereceiver comprising means to centrifuge the liquid from the ice receivedtherein.

10. In an apparatus for freeze dehydrating aqueous substances, acontainer for receiving an aqueous substance for freeze dehydration,refrigeration and heating means operatively connected to said containerfor respectively refrigerating and heating said chamber, an agitatorwithin said chamber, means connected with said agitator for lifting thesame out of said container, means tiltably supporting said container,and a receptacle at one side of said container to receive substancestherefrom upon tilting of the container relative to said receptacle,said receptacle being adapted for separating liquids and solidsdelivered thereto.

11. In an apparatus for freeze dehydrating aqueous substances, acontainer for receiving an aqueous substance for freeze dehydration,refrigeration and heating means engaging said container for respectivelyrefrigerating and heating said chamber, an agitator within said chamber,means connected with said agitator for lifting the same out of saidcontainer, means tiltably supporting said container, and a receptacle atone side of said container to receive substances therefrom upon tiltingof the container relative to said receptacle, said receptaclecornprising a centrifuge.

12. In an apparatus for freeze dehydrating aqueous substances, acontainer for receivingA an aqueous substance for freeze dehydration,refrigeration and heating means engaging said container for respectivelyrefrigerating and heating said chamber, an agitator within said chamber,means connected with said agitator for lifting the same out of saidcontainer, means tiltably supporting said container, a receptacle at oneside of said container to receive substances therefrom upon tilting ofthe container relative to said receptacle, said receptacle comprising acentrifuge, and a circulatory system connected between the centrifugeand said container through which at least a part of the fluid dischargedfrom the centrifuge is returned to said container.

13. A process for concentrating fruit juice to a predeterminedconcentration which comprises subjecting said juice to a series ofsuccessive coordinated freezing stages and wherein the freezing stagesare carried out in freezing containers at progressively lowertemperature, whereby water in the juice is frozen out as fine icecrystals which are formed during each freezing stage, flash heating thecontainer after each freezing stage to flash loose ice formed on theinner walls of the container, thereafter delivering all of the ice andliquid to a centrifuge whereby the ice is separated from the liquid, andrefluxing a portion of the recovered liquid along with ice seedingcrystals to the preceding stage, and recovering a final juiceconcentrate containing refluxed juice portions.

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